U.S. patent application number 16/304305 was filed with the patent office on 2021-07-22 for parallel multi-region imaging device.
This patent application is currently assigned to HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY. The applicant listed for this patent is HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY. Invention is credited to Qinglei HU, Pei LI, Xiaohua LV, Shaoqun ZENG.
Application Number | 20210223525 16/304305 |
Document ID | / |
Family ID | 1000005556351 |
Filed Date | 2021-07-22 |
United States Patent
Application |
20210223525 |
Kind Code |
A1 |
LV; Xiaohua ; et
al. |
July 22, 2021 |
PARALLEL MULTI-REGION IMAGING DEVICE
Abstract
The parallel multi-region imaging device includes a multi-focus
generation module, a spatial demodulation module, and a detection
module. The multi-focus generation module is configured to modulate
illumination light to generate a plurality of focuses in an
object-side, and to form a plurality of different illumination
regions, thereby generating multiple paths of signal light through
a sample to be imaged. The spatial demodulation module is
configured to make spatial energy distribution of each path of
signal light no longer overlap or make an overlapping region
smaller than a target requirement. The detection module is
configured to independently detect each path of signal light
passing through the spatial demodulation module, so as to implement
parallel multi-region imaging.
Inventors: |
LV; Xiaohua; (Hubei, CN)
; ZENG; Shaoqun; (Hubei, CN) ; HU; Qinglei;
(Hubei, CN) ; LI; Pei; (Hubei, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY |
Hubei |
|
CN |
|
|
Assignee: |
HUAZHONG UNIVERSITY OF SCIENCE AND
TECHNOLOGY
Hubei
CN
|
Family ID: |
1000005556351 |
Appl. No.: |
16/304305 |
Filed: |
September 18, 2018 |
PCT Filed: |
September 18, 2018 |
PCT NO: |
PCT/CN2018/106072 |
371 Date: |
November 26, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 21/02 20130101;
G02B 21/0036 20130101; H04N 5/2256 20130101; G02B 21/0032 20130101;
G02B 21/008 20130101 |
International
Class: |
G02B 21/00 20060101
G02B021/00; G02B 21/02 20060101 G02B021/02; H04N 5/225 20060101
H04N005/225 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 17, 2018 |
CN |
201810937498.2 |
Claims
1. A parallel multi-region imaging device, comprising: a
multi-focus generation module, a spatial demodulation module, and a
detection module; the multi-focus generation module being
configured to modulate illumination light to generate a plurality
of focuses in an object-side, and to form a plurality of different
illumination regions, thereby generating multiple paths of signal
light through a sample to be imaged; the spatial demodulation
module being configured to make spatial energy distribution of each
path of signal light no longer overlap or make an overlapping
region smaller than a target requirement; and the detection module
being configured to independently detect each path of signal light
passing through the spatial demodulation module, so as to implement
parallel multi-region imaging.
2. The parallel multi-region imaging device according to claim 1,
further comprising a spectroscope between the multi-focus
generating module and the spatial demodulation module, wherein the
spectroscope is configured to spatially separate the illumination
light and signal light returned from the sample to be imaged, so
that the illumination light output by the multi-focus generation
module is propagated to the sample to be imaged and meanwhile the
signal light returned from the sample to be imaged is propagated to
the spatial demodulation module.
3. The parallel multi-region imaging device according to claim 2,
wherein a beam splitting method of the spectroscope includes
splitting based on wavelength, splitting based on polarization
state, splitting based on spatial position, and attenuation type
splitting.
4. The parallel multi-region imaging device according to claim 3,
further comprising a scanning module behind the spectroscope,
wherein the scanning module is configured to change a propagation
direction, a divergence degree or a convergence degree of a beam,
so that a focus of the object-side of an objective lens or a
one-dimensionally focused line changes position in space, thereby
performing scanning.
5. The parallel multi-region imaging device according to claim 4,
wherein a scanning member in the scanning module includes
reflective type, transmissive type, or diffractive type.
6. The parallel multi-region imaging device according to claim 1,
further comprising a relay optical path, wherein the relay optical
path is configured to implement pupil matching between the scanning
module and an objective lens, so as to enable illumination light to
enter the objective lens to illuminate the sample to be imaged
within a target scanning range of the scanning module.
7. The parallel multi-region imaging device according to claim 2,
further comprising a relay optical path, wherein the relay optical
path is configured to implement pupil matching between the scanning
module and an objective lens, so as to enable illumination light to
enter the objective lens to illuminate the sample to be imaged
within a target scanning range of the scanning module.
8. The parallel multi-region imaging device according to claim 3,
further comprising a relay optical path, wherein the relay optical
path is configured to implement pupil matching between the scanning
module and an objective lens, so as to enable illumination light to
enter the objective lens to illuminate the sample to be imaged
within a target scanning range of the scanning module.
9. The parallel multi-region imaging device according to claim 4,
further comprising a relay optical path, wherein the relay optical
path is configured to implement pupil matching between the scanning
module and the objective lens, so as to enable illumination light
to enter the objective lens to illuminate the sample to be imaged
within a target scanning range of the scanning module.
10. The parallel multi-region imaging device according to claim 5,
further comprising a relay optical path, wherein the relay optical
path is configured to implement pupil matching between the scanning
module and the objective lens, so as to enable illumination light
to enter the objective lens to illuminate the sample to be imaged
within a target scanning range of the scanning module.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention belongs to the field of imaging, and
more particularly relates to a parallel multi-region imaging
device.
2. Description of Related Art
[0002] Imaging techniques are used to acquire spatial information
of a sample. A wide-field imaging technique uses area array
detection that can acquire optical information in an imaged region
at an exposure time, and is a way of acquiring information in
parallel. This way of acquiring information in parallel is fast (up
to several thousand frames per second), but has no tomography
capabilities. Tomography refers to acquisition of signals only in a
certain thin layer (such as a focal plane) and shielding out
signals in other regions (such as outside the focal plane) of a
space, thereby reducing mutual interference of signals at different
positions in the space, and further acquiring images with
high-definition and high-contrast ratio. Imaging techniques with
tomography capabilities mainly include a confocal imaging technique
and a nonlinear imaging technique.
[0003] The confocal imaging technique sets a pinhole conjugated
with an object point of an object space in an image-side of an
imaging system, and enables illumination light to converge to the
object point by a way of point illumination during imaging. A
signal sent by the object point converges to the pinhole of the
image-side and passes through the pinhole after being imaged by the
imaging system, and then is received by a detector. Although some
other regions outside the object point still have certain intensity
of illumination light, signals sent by these positions cannot pass
through the pinhole after passing through the imaging system, and
cannot be received by the detector, thereby being blocked. The
confocal imaging technique modulates the illumination intensity in
the object space by point illumination, and then blocks the signals
at other positions outside the object point through the pinhole,
thereby obtaining a tomography effect. Since both illumination and
detection are only for a certain point (not an infinitesimal point,
but a very small three-dimensional region relative to the imaging
range) in space. In order to acquire spatial information of the
sample, a scanner is needed for point scanning and point-by-point
detection, and signals of all points are spliced together to form
an image.
[0004] The nonlinear imaging technique is an imaging technique
based on nonlinear effect. Since the intensity of the nonlinear
effect has a high-order nonlinear relationship with the space-time
density of photons, there are many advantages that are different
from the linear imaging technique, such as high resolution, optical
tomography capabilities, and the like. Because of this nonlinear
feature, the conventional nonlinear imaging technique requires
focusing the illumination light to ensure that a sufficiently
strong nonlinear effect can be produced within the focus, and then
a scanner is used for scanning to form an image. Both of the above
imaging techniques with tomography capabilities require scanning
imaging, and scanning one surface or even a solid in space is time
consuming. Imaging speed is critical to a dynamic process of sample
observing. Even with high-speed scanners, since exposure is
performed on points in space in a serial mode, the single-point
exposure time is very limited, which is detrimental to signal
intensity and a signal-to-noise ratio. In order to increase the
imaging speed, a parallel detection mode can be introduced, such as
expanding single-point scanning to multi-point simultaneous
scanning or even line scanning. A large number of methods and
techniques have been put into practice, but most of them only
perform parallel detection on a lateral two-dimensional plane with
respect to an optical axis of the imaging system. Parallel
detection on spatial regions of different axial positions is
difficult due to a reason of the object-image relationship.
Although several methods for parallel detection on spatial regions
of different axial positions have been developed in the industry,
the limitations are large. One of the methods is to use pulsed
illumination to make signals at different axial positions multiplex
in time, and then demodulate acquired sequence signals for parallel
imaging. The limitations of this method are: firstly, the method
requires a high-speed signal acquisition system, because the
gain-bandwidth product of a signal amplifier is limited, the high
speed means a large bandwidth, resulting in small gain and
difficulty in detecting weak light; and secondly, the sample needs
to have a fast response to the illumination light, when the sample
is a fluorescent sample, some of the fluorescent substances have a
long fluorescence lifetime, which causes aliasing of the signals at
different positions in time and further causes incapability of
demodulation. A second one of the methods is to acquire
superimposed signals of multiple spatial regions at different axial
positions without distinction, and adopt an algorithm to perform
image processing by using prior knowledge of the sample, thereby
separating the superimposed signals into separate signals for each
spatial region. The limitations of this method are as follows:
firstly, it needs enough prior knowledge about the sample; and
secondly, the signals in the space need to be sparse, and if the
signals are relatively dense in space, the algorithm is prone to
misjudgment.
SUMMARY OF THE INVENTION
[0005] In view of the above defects or improvement requirements of
the prior art, the present invention provides a parallel
multi-region imaging device, thereby solving the technical problems
of difficulty in weak light detection, incapability of signal
demodulation, high proneness to misjudgment and the like in the
existing parallel multi-region imaging detection technique.
[0006] To achieve the above object, the present invention provides
a parallel multi-region imaging device, including: a multi-focus
generation module, a spatial demodulation module and a detection
module;
[0007] the multi-focus generation module is configured to modulate
illumination light to generate a plurality of focuses in an
object-side, and to form a plurality of different illumination
regions, thereby generating multiple paths of signal light through
a sample to be imaged;
[0008] the spatial demodulation module is configured to make
spatial energy distribution of each path of signal light to no
longer overlap or make an overlapping region smaller than a target
requirement; and
[0009] the detection module is configured to independently detect
each path of signal light passing through the spatial demodulation
module, so as to implement parallel multi-region imaging.
[0010] Preferably, between the multi-focus generating module and
the spatial demodulation module, the device further includes a
spectroscope; and
[0011] the spectroscope is configured to spatially separate the
illumination light and signal light returned from the sample to be
imaged, so that the illumination light output by the multi-focus
generation module is propagated to the sample to be imaged and
meanwhile the signal light returned from the sample to be imaged is
propagated to the spatial demodulation module.
[0012] Preferably, a beam splitting method of the spectroscope
includes splitting based on wavelength, splitting based on a
polarization state, splitting based on a spatial position and
attenuation type splitting.
[0013] Preferably, behind the spectroscope, the device further
includes a scanning module; and
[0014] the scanning module is configured to change a direction
propagation, a degree divergence or a degree convergence of a beam,
so that a focus of the object-side of an objective lens or a
one-dimensionally focused line changes position in space, thereby
performing scanning.
[0015] Preferably, a scanning member in the scanning module
includes reflective type, transmissive type, or diffractive
type.
[0016] Preferably, behind the scanning module, the device further
includes a relay optical path; and
[0017] the relay optical path is configured to implement pupil
matching between the scanning module and an objective lens, so as
to enable illumination light to enter the objective lens to
illuminate the sample to be imaged within a target scanning range
of the scanning module.
[0018] To sum up, compared with the prior art, the above technical
solution conceived by the present invention can achieve following
beneficial effects: the multi-focus generation module is used to
generate multiple different illumination regions on the object
space, so as to generate multiple paths of signal light. The
spatial demodulation module is used to make spatial energy
distribution of each path of signal light finally no longer overlap
(or only have little overlap). The detection module is used to
detect signals, thereby solving the technical problems of
difficulty in weak light detection, incapability of signal
demodulation, high proneness to misjudgment and the like in the
existing parallel multi-region imaging detection technique.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a structure diagram of a device according to an
embodiment of the present invention.
[0020] FIG. 2 is a structure diagram of another device according to
an embodiment of the present invention.
[0021] FIG. 3 is a structure diagram of a multi-focus generation
module according to an embodiment of the present invention.
[0022] FIG. 4 is a structure diagram of another multi-focus
generation module according to an embodiment of the present
invention.
[0023] FIG. 5 is a structure diagram of a spectroscope according to
an embodiment of the present invention.
[0024] FIG. 6 is a structure diagram of another spectroscope
according to an embodiment of the present invention.
[0025] FIG. 7 is a structure diagram of another spectroscope
according to an embodiment of the present invention.
[0026] FIG. 8 is a structure diagram of a spatial demodulation
module according to an embodiment of the present invention.
[0027] FIG. 9 is a structure diagram of another spatial
demodulation module according to an embodiment of the present
invention.
[0028] FIG. 10 is a structure diagram of another spatial
demodulation module according to an embodiment of the present
invention.
[0029] FIG. 11 is a structure diagram of a device according to an
embodiment of the present invention.
[0030] FIG. 12 is a structure diagram of another device according
to an embodiment of the present invention.
[0031] FIG. 13 is a structure diagram of another device according
to an embodiment of the present invention.
[0032] FIG. 14 is a structure diagram of another device according
to an embodiment of the present invention.
[0033] FIG. 15 is a structure diagram of another device according
to an embodiment of the present invention.
[0034] FIG. 16 is a structure diagram of another device according
to an embodiment of the present invention.
DESCRIPTION OF THE EMBODIMENTS
[0035] In order to make the objects, technical solutions and
advantages of the present invention more clear, the present
invention will be further described in detail below with reference
to the accompanying drawings and embodiments. It should be
understood that the specific embodiments described herein are
merely illustrative of the present invention and are not intended
to limit the present invention. Further, the technical features
involved in the various embodiments of the present invention
described below may be combined with each other as long as they do
not constitute a conflict with each other.
[0036] The present invention relates to a device for implementing
parallel multi-region imaging using a certain structure. The
imaging of the present invention refers to acquiring optical
information in space.
[0037] FIG. 1 shows a structure diagram of a device according to an
embodiment of the present invention, including a light source
module 1, a preprocessing module 2, a multi-focus generation module
3, a spectroscope 4, a scanning module 5, a relay optical path 6,
an objective lens 7, a spatial demodulation module 8, a detection
module 9, and a control-acquisition-processing module 10.
[0038] The light source module is configured to generate
illumination light. The light source may be an incoherent light
source (such as a xenon lamp, a halogen lamp, a light emitting
diode LED, etc.), also may be a coherent light source (such as a
continuous laser, a pulsed laser, a super luminescent diode SLD,
etc.), may be a broadband light source, and also may be a
narrowband or monochromatic source, and the type of the light
source including its emission spectrum is determined based on an
imaged sample and imaging requirements. The light source module, in
addition to the light source per se, may include other auxiliary
devices, such as a collimating lens that collimates output light or
a shaper that shapes an output light spot.
[0039] The preprocessing module is configured to process a beam, so
that the beam meets the requirements of subsequent optical paths,
such as implementing functions of beam expansion, polarization
state adjustment, power attenuation, etc.
[0040] The multi-focus generation module is configured to modulate
the illumination light, such that an object-side of an objective
lens finally generates two or more focuses (or two or more
one-dimensionally focused lines). The forms of the multi-focus
generation module include: forming multiple beams by using a
combination of beam splitters, then adjusting a light propagation
direction and convergence or divergence degree by using a
combination of lenses, and combining the multiple beams to form a
multi-focus beam; generating a multi-focus beam by a light
modulator, such a spatial light modulator (a device that performs
array modulation on the intensity or phase of light) or a digital
micromirror device (a device that performs digital modulation on
the intensity of light), etc., and other auxiliary devices (such as
dispersion compensation devices, apertures that block off unwanted
diffraction orders, etc.); an acousto-optic deflector or an
acousto-optic lens composed of an acousto-optic deflector; a phase
plate with phase modulation processed by a transparent material,
such as a diffraction grating, a Fresnel lens, a multi-focus phase
plate, etc.; an intensity type passive diffraction device, such as
a Daman grating, a Fresnel zone plate, etc.; a passive intensity
and phase mixed diffraction device; a lens array; and other types
of multi-focus generation methods. When the multi-focus generation
module includes an active device (such as the above-mentioned
spatial light modulator, digital micromirror device, acousto-optic
deflector, etc.), the multi-focus generation module is controlled
by the control-acquisition-processing module.
[0041] The spectroscope is configured to spatially separate the
illumination light from signal light, such that they do not overlap
in space and are far apart from each other, so that the
illumination light output by the multi-focus generation module is
propagated to the scanning module, and the signal light returned
from the scanning module is propagated to the spatial demodulation
module. A beam splitting method of the spectroscope includes
splitting based on wavelength, splitting based on polarization
state, splitting based on spatial position, and attenuation type
splitting, etc. The splitting based on wavelength means that when
the wavelengths of the illumination light and the signal light are
different, a wavelength sensitive device is used to make
propagation paths of the illumination light and the signal light
not overlap. For example, when the wavelength of the illumination
light is greater than the wavelength of the signal light, a
long-pass dichroic mirror is used, so that the illumination light
is transmitted through the dichroic mirror and the signal light is
reflected by the dichroic mirror; or a short-pass dichroic mirror
is used, so that the illumination light is reflected by the
dichroic mirror and the signal light is transmitted through the
dichroic mirror. The splitting based on polarization state means
that when the illumination light and the signal light are both
polarized light, a polarization sensitive device is used to make
the propagation paths of the illumination light and the signal
light not overlap. For example, when the polarization states of the
illumination light and the signal light are perpendicular, a
polarizing beam splitter may be used, such that one of the
illumination light and the signal light is transmitted through the
polarizing beam splitter and the other one thereof is reflected by
the polarizing beam splitter. If the illumination light propagated
to a sample and the signal light returned by the sample are
polarized light but there is no significant difference in the
polarization state, it is also possible to adjust the polarization
states of the illumination light and the polarized light by
inserting a polarization adjuster in a light path so as to make a
difference, and then the polarization sensitive device is used for
perform beam splitting. For example, when the light emitted by a
light source is linearly polarized light and the signal light
returned by the sample per se is in the same polarization state as
the illumination light irradiated onto the sample, a quarter-wave
plate can be added at a certain position in the optical path
between the polarization sensitive device for beam splitting and
the sample, and the polarization state of the light is rotated
after the light passes through the quarter-wave plate twice, so
that the illumination light and the signal light at the
polarization sensitive device are different in polarization state
and then split. When the quarter-wave plate is properly placed in
position and angle, the polarization states of the signal light and
the illumination light at the polarization sensitive device for
beam splitting are just perpendicular, and at this time, using the
polarizing beam splitter results in the best beam splitting effect.
The splitting based on spatial position means that when the
illumination light and the signal light do not completely overlap
in space but are close to each other such that it is not convenient
to separately detect the signal light, a lens, a telescope, a
mirror, a prism, or other optical devices are used to amplify the
difference between the illumination light and the signal light in
the propagation path, thereby facilitating detection of the signal
light. For example, when the beam directions of the illumination
light and the signal light are very close to each other and
indistinguishable but the spatial positions do not overlap, a
reflective mirror can be utilized such that it does not affect the
propagation of the illumination light but reflects the signal
light, thereby clearly distinguishing the signal light and the
illumination light in space. The attenuation type splitting means
that the difference between the physical properties of the
illumination light and the signal light is not utilized, and the
illumination light and the signal light are spatially split by
directly using a method of sacrificing energy. For example, a half
mirror (or another transflective lens) is used, so that the
illumination light is partially transmitted and partially
reflected, the reflected part is not used, and only the transmitted
part is used for illumination. The signal light is also partially
transmitted and partially reflected, and only the reflected part of
the signal light is detected. Although the illumination light also
has a reflected part, since the illumination light and the signal
light are reflected in different directions at this time, they can
be spatially split; and of course, the selected
transmission-reflection relationship can also be reversed (that is,
the reflected part of the illumination light is used for
illumination) as long as the final effect is that the propagation
paths of the illumination light and the reflected light can be
spatially split.
[0042] The scanning module is configured to change a propagation
direction or a divergence degree (or a convergence degree) of a
beam, so that the focus of the object-side of an objective lens (or
a one-dimensionally focused line) changes position in space,
thereby performing scanning. A scanning member in the scanning
module includes a reflective type, transmissive type or diffractive
type. Specifically, the types of scanning member include: a
galvanometer mirror, a resonant mirror, a rotating polygon mirror,
a piezoelectric galvanometer (a scanning member that is driven by
piezoelectric ceramics and can rotate or translate the reflective
mirror), a deformable mirror, an electro-optic deflector (a device
that changes the beam propagation direction based on an
electro-optic effect), an electro-optic lens (a device that changes
the convergence degree and the divergence degree of the beam based
on the electro-optic effect), an acousto-optic deflector (a device
that changes the beam propagation direction based on the
acousto-optic effect), an acousto-optic lens (a device that is
formed by combining an acousto-optic deflector, and can change the
convergence degree and the divergence degree of the beam and also
can change the direction of main rays in the beam), a tunable
acoustic-induced gradient index lens (a device that generates a
refractive index profile in a medium based on mechanical
vibrations, so as to implement phase modulation, thereby changing
the convergence degree and the divergence degree of the beam), a
variable-focus lens (a device that changes the shape of the medium
based on the mechanical deformation or an electrowetting effect,
thereby changing the convergence degree and the divergence degree
of the beam), a spatial light modulator (a device that performs
array modulation on the intensity or phase of light), a digital
micromirror device (a device that performs digital modulation on
the intensity of light), etc. Preferably, the scanning module uses
a galvanometer mirror, a resonant mirror or a piezoelectric
galvanometer to achieve better beam quality and transmission
efficiency. When a scanning member having dispersion (for example,
an acousto-optic deflector) is used, the scanning module further
includes a dispersion compensating device whose function is to make
the light having different wavelength components in the optical
path to have identical direction and convergence or divergence
degree in space.
[0043] The relay optical path is configured to implement pupil
matching between the scanning module and the objective lens, that
is, in a suitable scanning range of the scanning module, the
illumination light can enter the objective lens as much as
possible, so as to illuminate the sample. An ideal state of the
pupil matching is that an exit pupil of the scanning module
completely coincides with an entrance pupil of the objective lens
(here, the entrance pupil and the exit pupil are relative to the
propagation direction of the illumination light). If the exit pupil
diameter of the scanning module (for a reflective scanner such as a
galvanometer mirror, the exit pupil diameter is determined by the
diameter of the illumination beam) is equivalent to the entrance
pupil diameter of the objective lens, the magnification of the
relay optical path is 1:1; and if the exit pupil diameter of the
scanning module is not equivalent to the entrance pupil diameter of
the objective lens, preferably, the relay optical path should have
a certain lateral magnification effect such that the exit pupil
diameter of the scanning module is equivalent to the entrance pupil
diameter of the objective lens. Preferably, the relay optical path
should use a 4f optical system, and the 4f optical system means
that the relay optical path includes front and back lenses (here,
the front and back are relative to the propagation direction of the
illumination light), the front lens and the back lens are both
positive lenses, the optical axes of them are coincident, and a
back focal plane of the front lens coincides with a front focal
plane of the back lens. Preferably, the exit pupil of the scanning
module is located on the front focal plane of the front lens and
coincides with a center, and the entrance pupil of the objective
lens is located on the back focal plane of the back lens and
coincides with the center. If the scanning module is so close to
the objective lens that it is not necessary to relay through the
lens when the illumination light is enabled to enter the objective
lens as much as possible to illuminate the sample in a suitable
scanning range of the scanning module, the relay optical path can
also be omitted.
[0044] The objective lens is an optical device with a focusing
function. It is called an objective lens because it is close to an
object (i.e., a sample) to be imaged. Specifically, the objective
lens includes lenses of different structures such as single lenses,
glued lenses, lens assemblies and the like, includes lenses of
different focusing modes such as refractive lenses, reflective
lenses, diffractive lenses and the like, and includes lenses of
different surface types such as curved lenses, gradient index
lenses and the like.
[0045] The function of the spatial demodulation module is to
significantly split the spatial position of the signal light
emitted by the sample at different illumination focus (or
one-dimensionally focused illumination line) positions in the
object-side of the objective lens in spatial position, thereby
performing detection respectively. Preferably, the spatial
demodulation module is composed of a focusing lens and a perforated
mirror. The perforated mirror is a mirror having a through hole,
preferably a planar mirror. The hole of the perforated mirror and a
certain illumination focus of the object-side of the objective lens
are in a positionally object-image conjugated relationship. The
object-image relationship is composed of an imaging system
consisting of all optical devices in the process of signal light
propagation to the pinhole, and in the simplest case, the imaging
system includes (without considering the planar mirror in the
optical path) the focusing lens, a relay optical path, and the
objective lens in the spatial demodulation module. There are a
plurality of illumination focuses (or one-dimensionally focused
illumination lines) in the object-side of the objective lens, and
each focus (or one-dimensionally focused illumination line)
generates a path of signal light. Before the signal light enters
the spatial demodulation module, several paths of the signal light
overlap in space, making it difficult to distinguish them. Since
the hole of the perforated mirror and a certain illumination focus
of the object-side of the objective lens are in an object-image
conjugated relationship, the signal light emitted by samples at
other illumination focus positions in the object-side of the
objective lens certainly cannot pass through the pinhole smoothly,
so most of the signal light emitted from these other positions is
reflected by the perforated mirror, and thus, the signal light
emitted from the object point which is in an object-image
conjugated relationship with the pinhole can be demodulated by
using the perforated mirror. When there are only two paths of
signal light, demodulation can be performed by using one perforated
mirror; and when there are N paths of signal light, demodulation
can be performed by using N-1 perforated mirrors. When there are
multiple paths of signal light, a combination of the focusing lens
and the perforated mirror is used, and each path of signals is
sequentially demodulated by using the feature that the pinhole of
the perforated mirror and the object point of a certain path of
signal are in the object-image conjugated relationship. After
demodulation, each path of signal light finally has a different
propagation path in space. When the illumination is not focal point
illumination but focus line illumination, the pinhole in the mirror
is changed to a slit that is positionally in an object-image
conjugated relationship with the focal line of illumination. The
pinhole and the slit are positionally in an object-image conjugated
relationship with the illumination point or illumination line of
the object-side, but do not need to strictly satisfy the
object-image conjugated relationship in geometrical dimensions. The
perforated (or slit) mirror neither can ensure a certain path of
signal to absolutely pass through the pinhole (or slit), nor can
ensure other paths of signals to absolutely not pass through the
pinhole (or slit) and be reflected, but should ensure that the
signal intensity of the part of the corresponding path of signal
passing through the pinhole (or slit) is greater than the signal
intensity of the reflected part, and that the signal intensity of
the reflected part of other paths of signals is greater than that
of the part passing through the pinhole (or slit). The spatial
demodulation module includes a passive type and an active type. The
passive spatial demodulation module is composed of passive devices
(such as mirrors, lenses and other passive optical components), and
the active spatial demodulation module is composed of active
devices (such as digital micromirror devices and other active
devices). When the spatial demodulation module is composed of the
active devices, the active devices are controlled by the
control-acquisition-processing module. In summary, no matter which
device is used specifically, the principle of spatial demodulation
is that: there are multiple paths of light, and the focusing
position of each path is different; a device is used to select a
certain path separately, so that this path is propagated in a
certain direction, and the other paths are propagated in other
directions, ensuring that the propagation path of this path is
split from that of the other paths in space, thereby demodulating
this path separately, demodulating the multiple paths of light
sequentially, and finally distinguishing all the paths. Of course,
if a device can only demodulate one path of signal, it is
inevitable to perform demodulation sequentially using the
abovementioned cascade manner. If the device per se has the
function of parallel demodulation of multiple paths, it is also
possible to perform parallel demodulation directly or parallel and
cascade mixed demodulation. A device does not have to completely
demodulate one or several paths of signals, as long as it can
distinguish the multiple paths of signals to some extent, and each
path of signals can be demodulated by cascading multiple devices.
After demodulation, the propagation paths of the paths of signals
finally do not overlap in space, or the spatial energy distribution
of each path of signals does not overlap (or has only little
overlap).
[0046] The detection module is configured to independently detect
each path of signals demodulated by the spatial demodulation
module. The detection module is mainly composed of photodetectors,
including area array photodetectors (area array CCD detectors and
area array CMOS detectors), line array photodetectors (line array
CCD detectors and line array CMOS detectors), photomultiplier
tubes, photodiodes, and other devices capable of converting an
optical signal into an electrical signal. The number of detectors
in the detection module is based on the number of signal channels
required. Preferably, in addition to the detectors, the detection
module further includes other devices beneficial to signal
detection. For example, when the signal light is propagated to the
position of a photosensitive surface of the detector such that a
light spot is so large to cause signal loss, a focusing lens is
placed in front of the detector to reduce the light spot; when the
signal light is fluorescence, a cut-off filter is placed in front
of the detector to avoid interference of light other than a
fluorescent band; and when there is interference of other paths of
signal light having no significant difference in wavelength from
this path of signal light in space, a combination of the focusing
lens and the pinhole is used, so that this path of signal light
enters the detector after passing through the pinhole, thereby
inhibiting interference.
[0047] The functions of the control-acquisition-processing module
include: controlling all active devices (mainly the scanner in the
scanning module, and also including active devices in other
modules) to operate in the imaging process; acquiring signals
output by the detector, including signal amplification, filtering,
analog-to-digital conversion and other operations, such that the
original signal output by the detector changes to enable data
processing; and processing the acquired signals, including
splicing, grey level transformation and other operations, such that
the acquired data is displayed or stored in the form of images or
other data.
[0048] An imaging process of the parallel multi-region imaging
method according to an embodiment of the present invention is as
follows: the illumination light is emitted by the light source
module 1, passes through the preprocessing module 2 to achieve a
suitable beam diameter, optical power or polarization state, then
enters the multi-focus generation module 3. The multi-focus
generation module 3 modulates the illumination light to generate
two or more sub-beams of different directions or focusing degrees,
and then the illumination light is continuously propagated to the
spectroscope 4, is transmitted to the scanning module 5 after
passing through the spectroscope 4, is propagated to the objective
lens 7 through the relay optical path 6, and forms two or more
focuses (or one-dimensionally focused illumination lines) in the
object-side through the objective lens 7. After the illumination
light is irradiated onto the sample 0, signal light is generated on
the sample 0 by reflection, scattering or fluorescence effects and
the like. The signal light is collected by the objective lens 7 and
is propagated to the scanning module 5 through the relay optical
path 6. The scanning module 5 performs scanning under the control
of the control-acquisition-processing module 10, the signal light
is propagated to the spectroscope 4 through the scanning module 5.
The spectroscope continuously propagates the signal light along a
spatial path different from the illumination light, then the signal
light enters the spatial demodulation module 8, the spatial
demodulation module 8 spatially splits each path of signal light
that is generated by each illumination sub-beam on the sample, the
detection module 9 detects the paths of signal light after
splitting, and the control-acquisition-processing module 10
acquires and processes electrical signals output by the detection
module 9 and finally displays or stores the processed electrical
signals in the form of images or other data.
[0049] The above structure and imaging process use the same
objective lens for both illumination and signal light collection.
As shown in FIG. 2, embodiments of the present invention also
include other forms of structures and imaging processes, for
example, using two objective lenses for illumination and signal
light collection respectively. The variation of the structure lies
in the numbers of the scanning modules, the relay optical paths and
the objective lenses are two respectively, and the spectroscope is
disposed behind the second scanning module. The imaging process is:
the illumination light is emitted by the light source module 1,
passes through the preprocessing module 2 to achieve a suitable
beam diameter, optical power or polarization state, enters the
multi-focus generation module 3, and is modulated by the
multi-focus generation module 3 to generate two or more sub-beams
of different directions or focusing degrees, and then the
illumination light is continuously propagated to a first scanning
module 5a, is propagated to a first objective lens 7a through a
first relay optical path 6a, and forms two or more focuses (or
one-dimensionally focused illumination lines) in the object space
through the first objective lens 7a. After the illumination light
is irradiated onto the sample 0, signal light is generated on the
sample 0 by reflection, scattering or fluorescence effects and the
like. The signal light is collected by a second objective lens 7b
and is propagated to a second scanning module 5b through a second
relay optical path 6b, the second scanning module 5b performs
scanning under the control of the control-acquisition-processing
module 10, the illumination light is then propagated to the
spectroscope 4 through the second scanning module 5b. The
spectroscope 4 filters out a part of the illumination light that is
aliased with the signal light, then the signal light is propagated
to the spatial demodulation module 8. The spatial demodulation
module 8 spatially splits each path of signal light that is
generated by each illumination sub-beam on the sample. The
detection module 9 detects the paths of signal light after
splitting, and the control-acquisition-processing module 10
acquires and processes electrical signals output by the detection
module 9 and finally displays or stores the processed electrical
signals in the form of images or other data.
[0050] For the structure of a single objective lens, based on the
principle of reversibility of a light path, the spatial position of
the signal light after passing through the scanning module does not
change with the scanning of the scanning module, which is called
back scanning. For the structure of two objective lenses, the
scanning process of the second scanning module 5b and the first
scanning module 5a should be synchronized to implement the effect
of back scanning. The function of the spectroscope 4 is also
changed, and only filtering out the illumination light that is
aliased with the signal light is needed.
[0051] A specific implementation 1 of the multi-focus generation
module according to an embodiment of the present invention is shown
in FIG. 3. A half-wave plate 31a is disposed in front of a
polarizing beam splitting prism 32a. The polarizing beam splitting
prism 32a splits input light into a reflected beam and a
transmitted beam, and the half-wave plate 31a is used to adjust an
energy ratio of the reflected beam to the transmitted beam of the
polarizing beam splitting prism 32a. A half-wave plate 31b is
disposed in front of a polarizing beam splitting prism 32b, the
polarizing beam splitting prism 32b splits the reflected light of
the polarizing beam splitting prism 32a into two beams, and the
half-wave plate 31b is used to adjust an energy ratio of the
reflected light to the transmitted light of the polarizing beam
splitting prism 32b. By using the beam splitting effects of the
polarizing beam splitting prisms 32a and 32b, three sub-beams are
finally obtained. Among them, a first sub-beam is not modulated by
a lens, a second sub-beam is modulated by a lens 34a and a lens
34b, a third sub-beam is modulated by a lens 34c and a lens 34d,
and the direction and focusing/divergence degree of the modulated
beam are changed. The first sub-beam is reflected by a mirror 33a,
and the third sub-beam is reflected by a mirror 33b. The first
sub-beam is transmitted through a polarizing beam splitting prism
32c, the second sub-beam is reflected by a polarizing beam
splitting prism 32c. The first and second sub-beams are combined,
and then is modulated by a half-wave plate 31c to the polarization
state. The function of the half-wave plate 31c is to take a
suitable polarization state of the combined beam of the first and
second sub-beams, such that the combined beam is reflected by a
polarizing beam splitting prism 32d. The third sub-beam is
transmitted by the polarizing beam splitting prism 32d. After
passing through the polarizing beam splitting prism 32d, the three
sub-beams are all combined. At this time, although the directions
and divergence or focusing degrees of the three sub-beams are not
the same, there is still a large overlap in space.
[0052] A specific implementation 2 of the multi-focus generation
module according to the embodiment of the present invention is
shown in FIG. 4. The spatial light modulator 35 generates a
specific modulation pattern under the control of the
control-acquisition-processing module 10. Different modulation
patterns can generate different multi-focus distributions.
Specifically, the phase modulation distribution that varies
linearly with space is used to change the direction of emergent
light, and the phase modulation pattern distributed in the form of
a lens modulation function with space is used to change the
focusing or divergence degree of the emergent light (the lens
modulation function is circularly symmetrical, and its circle
center position can also be used to change the direction of the
emergent light).
[0053] A specific implementation 1 of the spectroscope according to
the embodiment of the present invention is shown in FIG. 5. A
dichroic film 41 has different reflectances and transmittances for
light of different wavelengths, and is characterized by having a
high transmittance for long-wavelength light and having a high
reflectance for short-wavelength light, so that the propagation
paths of light of different wavelengths are different.
[0054] A specific implementation 2 of the spectroscope according to
the embodiment of the present invention is shown in FIG. 6. A
polarizing beam splitting prism 42 has different reflectances and
transmittances for light of different polarization state, and is
characterized by having a high transmittance for light having a
polarization state of p and having a high reflectance for light
having a polarization state of s, so that the propagation paths of
light of different wavelengths are different.
[0055] A specific implementation 3 of the spectroscope according to
the embodiment of the present invention is shown in FIG. 7. An edge
of a mirror 43 is disposed between two beams, so that it reflects
one path of light, and the other path is continuously propagated
without being blocked, thereby making the light of which the
propagation path does not overlap in space further split in
space.
[0056] A specific implementation 1 of the spatial demodulation
module according to the embodiment of the present invention is
shown in FIG. 8. The middle of a mirror surface of the perforated
mirror 81 has a pinhole permeable to light. There are two paths of
light in space, one path has a focus that overlaps with the pinhole
of the perforated mirror 81, such that this path may pass through
the pinhole to be continuously propagated, and the other path has a
focus that does not overlap with the pinhole of the perforated
mirror 81, such that most energy of this path may be reflected by
the mirror. A beam 80a that finally passes through the pinhole and
the reflected beam 80b no longer overlap in space.
[0057] A specific implementation 2 of the spatial demodulation
module according to the embodiment of the present invention is
shown in FIG. 9. A digital micromirror device 82 generates a
specific modulation pattern under the control of the
control-acquisition-processing module 10. There are two paths of
light in space, one path is focused on a working surface of the
digital micromirror device 82, a micromirror at the focus position
of this path in the digital micromirror device 82 is deflected to
one state, and other micromirrors are deflected to another state;
and thus, the path of light focused to the digital micromirror
device 82 is reflected by the digital micromirror device 82 to a
certain direction, and the other path of light is reflected to
another direction, thereby finally forming beams 80c and 80d that
do not overlap in space.
[0058] A specific implementation 3 of the spatial demodulation
module according to the embodiment of the present invention is
shown in FIG. 10. A spatial light modulator 83 generates a specific
modulation pattern under the control of the
control-acquisition-processing module 10. There are three paths of
light in space, and they have different focusing degrees. The
pattern on the spatial light modulator 83 is a deformed grating
(off-axis Fresnel zone plate or off-axis holographic lens) that
cooperates with a lens 831 to diffract three paths of light of
different focusing degrees to different diffraction orders, thereby
finally forming beams 80e, 80f and 80g that do not overlap in
space.
[0059] A specific implementation 1 of an overall structure
according to the embodiment of the present invention is shown in
FIG. 11. Laser light emitted by a femtosecond laser 11 is expanded
by a preprocessing module composed of a lens 21a and a lens 21b and
is then incident on the spatial light modulator 35, and the spatial
light modulator modulates the wave front to generate two focuses. A
multi-focus beam is relayed through a lens 351a and a lens 351b and
passes through the dichroic mirror 41, and then is incident on a
two-axis scanning module composed of a galvanometer mirror 51a and
a galvanometer mirror 51b, after being scanned by the scanning
module, it is incident on an objective lens 71 through a relay lens
61a and a relay lens 61b, and is focused on the sample 0 through
the objective lens 71. The femtosecond laser generates fluorescence
in the sample, a fluorescence signal is collected by the objective
lens 71, returns along a path, and is finally incident on the
dichroic mirror 41 and reflected by the dichroic mirror 41. After
the reflected light is focused by a lens 811, one path of light
passes through the pinhole of the perforated mirror 81 and is
detected by a photomultiplier tube 91a, and another path is
reflected by the perforated mirror 81 and is detected by a
photomultiplier tube 91b. The control-acquisition-processing module
is not shown in the figure. The spatial light modulator 35 and the
galvanometer mirrors 51a and 51b are all controlled by the
control-acquisition-processing module, and output signals of the
photomultiplier tubes 91a and 91b are acquired by the
control-acquisition-processing module.
[0060] A specific implementation 2 of the overall structure
according to the embodiment of the present invention is shown in
FIG. 12. The laser light emitted by the femtosecond laser 11 is
expanded by the preprocessing module composed of the lens 21a and
the lens 21b, and is incident on a polarizing beam splitting prism
321a after the polarization state is adjusted by the half-wave
plate 31a. The polarizing beam splitting prism 321a splits the
light into two paths, one path is incident on a polarizing beam
splitting prism 321b after the convergence and divergence degrees
are adjusted by the lens 34a and the lens 34b, the other path is
reflected by reflective mirrors 331a and 331b and also incident on
the polarizing beam splitting prism 321b, and the polarizing beam
splitting prism 321b combines the two paths of light. The combined
light is reflected by a reflective mirror 331c, relayed by the lens
351a and the lens 351b, incident on the two-axis scanning module
composed of the galvanometer mirror 51a and the galvanometer mirror
51b after passing through the dichroic mirror 41, after being
scanned by the scanning module, it is incident on the objective
lens 71 through the relay lens 61a and the relay lens 61b, and is
focused on the sample 0 through the objective lens 71. The
femtosecond laser generates fluorescence in the sample, a
fluorescence signal is collected by the objective lens 71, returns
along a path, and is finally incident on the dichroic mirror 41 and
reflected by the dichroic mirror 41. After the reflected light is
focused by a lens 811, one path of light passes through the pinhole
of the perforated mirror 81 and is detected by a photomultiplier
tube 91a, and the other path is reflected by the perforated mirror
81 and is detected by a photomultiplier tube 91b. The
control-acquisition-processing module is not shown in the figure.
The galvanometer mirrors 51a and 51b are both controlled by the
control-acquisition-processing module, and output signals of the
photomultiplier tubes 91a and 91b are acquired by the
control-acquisition-processing module.
[0061] A specific implementation 3 of the overall structure
according to the embodiment of the present invention is shown in
FIG. 13. The laser light emitted by the femtosecond laser 11 is
expanded by the preprocessing module composed of the lens 21a and
the lens 21b and incident on a reflection grating 361. The
reflection grating 361 is used to compensate spatial dispersion of
a digital micromirror device 36, emergent light of the reflection
grating 361 is incident on the digital micromirror device 36 after
passing through the dichroic mirror 41, and the digital micromirror
device 36 simultaneously implements the functions of multi-focus
generation and scanning. After passing through the digital
micromirror device 36, light is incident on the objective lens 71
through the relay lenses 61a and 61b, and is focused by the
objective lens 71 to the focus. The femtosecond laser generates
fluorescence in the sample, a fluorescence signal is collected by
the objective lens 71, returns along the path, and is finally
incident on the dichroic mirror 41 and is reflected by the dichroic
mirror 41. After the reflected light is compensated by a dispersion
compensation module 49 and is focused by the lens 811. One path of
light passes through the pinhole of the perforated mirror 81 and is
detected by the photomultiplier tube 91a, and the other path is
reflected by the perforated mirror 81 and detected by the
photomultiplier tube 91b. The control-acquisition-processing module
is not shown in the figure. The digital micromirror device 36 is
controlled by the control-acquisition-processing module, and output
signals of the photomultiplier tubes 91a and 91b are acquired by
the control-acquisition-processing module.
[0062] A specific implementation 4 of the overall structure
according to the embodiment of the present invention is shown in
FIG. 14. The laser light emitted by the femtosecond laser 11 is
expanded by the preprocessing module composed of the lens 21a and
the lens 21b and then is incident on a transmission grating 352.
The transmission grating 352 is used to compensate the spatial
dispersion of the spatial light modulator 35, emergent light of the
transmission grating 352 is incident on the spatial light modulator
35. The spatial light modulator modulates the wave front to
generate two focuses. A multi-focus beam is relayed by the lens
351a and the lens 351b, passes through the dichroic mirror 41, and
is incident on a double-axis scanning module composed of an
acousto-optic deflector 52a and an acousto-optic deflector 52b,
after being scanned by the scanning module, incident on the
objective lens 71 through the relay lens 61a and the relay lens
61b, and is focused onto the sample 0 through the objective lens
71. The femtosecond laser generates fluorescence in the sample, a
fluorescence signal is collected by the objective lens 71, returns
along a path, and is finally incident on the dichroic mirror 41 and
reflected by the dichroic mirror 41. After the reflected light is
compensated by the dispersion compensation module 49 and focused by
the lens 811, one path of light passes through the pinhole of the
perforated mirror 81 and is detected by the photomultiplier tube
91a, and the other path is reflected by the perforated mirror 81
and detected by the photomultiplier tube 91b. The
control-acquisition-processing module is not shown in the figure.
The spatial light modulator 35 and the acousto-optic deflectors 52a
and 52b are all controlled by the control-acquisition-processing
module, and output signals of the photomultiplier tubes 91a and 91b
are acquired by the control-acquisition-processing module.
[0063] A specific implementation 5 of the overall structure
according to the embodiment of the present invention is shown in
FIG. 15. The laser light emitted by the femtosecond laser 11 is
expanded by the preprocessing module composed of the lens 21a and
the lens 21b and then is incident on the transmission grating 352.
The transmission grating 352 is used to compensate the spatial
dispersion of the spatial light modulator 35, the emergent light of
the transmission grating 352 is incident on the spatial light
modulator 35. The spatial light modulator modulates the wave front
to generate two focuses. A multi-focus beam is relayed by the lens
351a and the lens 351b, passes through the dichroic mirror 41, and
is incident on the double-axis scanning module composed of the
galvanometer mirror 51a and the galvanometer mirror 51b, after
being scanned by the scanning module, incident on the objective
lens 71 through the relay lens 61a and the relay lens 61b, and is
focused onto the sample 0 through the objective lens 71. The
femtosecond laser generates fluorescence in the sample, a
fluorescence signal is collected by the objective lens 71, returns
along a path, and finally incident on the dichroic mirror 41 and
reflected by the dichroic mirror 41. The reflected light is
incident on the digital micromirror device 83, and the digital
micromirror device 83 generates a deformed grating (off-axis
Fresnel zone plate), so that one path of light is focused to a
pinhole 381a and detected by the photomultiplier tube 91a, and the
other path is focused to a pinhole 831b and detected by the
photomultiplier tube 91b. The control-acquisition-processing module
is not shown in the figure. The spatial light modulator 35, the
galvanometer mirrors 51a and 51b, and the digital micromirror
device 83 are all controlled by the control-acquisition-processing
module, and simultaneously, output signals of the photomultiplier
tubes 91a and 91b are acquired by the
control-acquisition-processing module.
[0064] A specific implementation 6 of the overall structure
according to the embodiment of the present invention is shown in
FIG. 16. The laser light emitted by a femtosecond laser 11 is
expanded by the preprocessing module composed of the lens 21a and
the lens 21b, and is then incident on a transmission grating 352.
The transmission grating 352 is used to compensate the spatial
dispersion of the spatial demodulator 35. The emergent light of the
transmission grating 352 is incident on the spatial light modulator
35, the spatial light modulator modulates the wave front to
generate multiple focuses, and the multi-focus beam is relayed by
the lens 351a and the lens 351b, passes through the dichroic mirror
41, and is incident on a double-axis scanning module composed of a
galvanometer mirror 51a and a galvanometer mirror 51b, scanned by
the scanning module, incident on the objective lens 71 through the
relay lens 61a and the relay lens 61b, and focused onto the sample
0 through the objective lens 71. The femtosecond laser generates
fluorescence in the sample, a fluorescence signal is collected by
the objective lens 71, returns along a path, and is finally
incident on the dichroic mirror 41 and reflected by the dichroic
mirror 41. The reflected light is relayed by the lens 841a and the
lens 841b and incident on a modulator 84. A modulation function of
the modulator 84 is an n-th order function of space coordinates
(n.gtoreq.2), which can be expressed as t(x,
y)=Ae.sup.i[a(x.sup.n.sup.+y.sup.n.sup.)+b], where A is an
intensity modulation function and defaults to a real constant, and
a and b are real constants. When n=2, the modulator appears a lens.
When n=3, the emergent light of the modulator 84 appears as an Airy
beam. The modulator 84 is a passive modulation device that is
fabricated from a transparent material. The modulator 84 may also
be a spatial light modulator or a digital micromirror device. When
the modulator 84 is the digital micromirror device, its pattern is
a binarization result of the modulation function, for example,
cosine is taken for a phase, and then binarized according to a
threshold. After passing through the modulator 84, the light
exhibits a characteristic of focusing. If the axial positions of
the multiple focuses generated by the spatial light modulator 35
are the same, then when n=2, that is, when the modulator 84 is a
lens, the different focuses can be focused on the same plane and
are in different horizontal positions. If the multiple focuses
generated by the spatial light modulator 35 have different axial
positions, the lens is directly used for focusing, a defocused
light spot and a focused light spot may overlap, and spatial
demodulation cannot be performed. Therefore, taking n>2, the
focal depth of the focused light spot behind the modulator 84 is
greater than the focal depth of the lens focus under the same
numerical aperture, so that the phenomenon of overlapping of the
defocused light spot and the focused light spot is eliminated, and
different focuses have different horizontal positions after
focusing. Different focuses are focused on the same plane and have
different horizontal positions, thereby implementing spatial
demodulation. A detector 92 is located in a focal region behind the
modulator 84, and at this time, the signal light appears on the
detector 92 as focused light spots having different horizontal
positions. The detector 92 is an array detector, such as a
multi-anode photomultiplier tube, an array avalanche diode, an area
array CMOS sensor, an area array CCD sensor, etc., so that signals
of different focused light spots can be acquired. The
control-acquisition-processing module is not shown in the figures.
The spatial light modulator 35, the galvanometer mirrors 51a and
51b and other active devices are all controlled by the
control-acquisition-processing module, and output signals of the
detector 92 are acquired by the control-acquisition-processing
module.
[0065] Those skilled in the art will readily understand that the
above description is only the exemplary embodiments of the present
invention, and is not intended to limit the present invention. Any
modifications, equivalent substitutions and improvements made
within the spirit and principle of the present invention shall fall
within the protection scope of the present invention.
* * * * *